This standard BS ISO 8664:2018 Tyres for agricultural tractors and machines. Code-designated and service-description marked radial drive-wheel tyres is classified in these ICS categories:
83.160.30 Tyres for agricultural machinery
This document specifies the marking, dimensions, load ratings and reference speeds for code-designated agricultural tractor drive-wheel tyres with service description (load index and speed symbol).
It applies to tyres of radial construction in the speed categories 40 km/h (speed symbol A8), and 50 km/h (speed symbol B).
NOTE Code designated series of:
diagonal (ply rating marked) tyres for agricultural tractors and machines are specified in ISO 4251‑1 and ISO 4251‑2;
tyres for logging and forestry machines are specified in ISO 188071;
tyres for construction/industrial tractors are specified in ISO 13442.